Recently I downloaded a file from one of our production server, did some changes and reviewed it in BIDS and everything looked good. However when I tried to upload the file in the Report Manager got a strange error

The report definition is not valid. Details: ‘.’, hexadecimal value 0x00, is an invalid character. Line 1570, position 10. (rsInvalidReportDefinition)

Since the error message was talking about Report Definition is not valid, checked whether I have corrected the report in appropriate version (we have SSRS 2005, 2008 & R2).

I opened the code behind of the RDL by clicking the “View Code” option in BIDS and looked at the line mentioned in the error message. I was surprised to see few blank spaces after the end of the Report tag and BIDS had highlighted it as an error.

I just simply deleted it, saved and built. Then it worked fine. However I still could not figure out how it was added